Wireless can be hit or miss as its very dependent on how good the signal is, there are lots of things that can interfere with wireless signals in a house or office. It could be that you are too far from the router or something is preventing a clear signal. One of the things you have to keep in mind with VoIP is that audio is very sensitive to packet loss or other network problems and thus wireless works well for e-mail and web but not always for VoIP. You could try buying a newer series linksys router and take if back if it does not improve the situation.